55 research outputs found

    Control failure likelihood and spatial dependence of insecticide resistance in the tomato pinworm, Tuta absoluta

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    Insecticide resistance is a likely cause of field control failures of Tuta absoluta, but the subject has been little studied. Therefore, resistance to ten insecticides was surveyed in seven representative field populations of this species. The likelihood of control failures was assessed, as well as weather influence and the spatial dependence of insecticide resistance. No resistance or only low resistance levels were observed for pyrethroids (bifenthrin and permethrin), abamectin, spinosad, Bacillus thuringiensis and the mixture deltamethrin + triazophos (<12.5-fold). In contrast, indoxacarb exhibited moderate levels of resistance (up to 27.5-fold), and chitin synthesis inhibitors exhibited moderate to high levels of resistance (up to 222.3-fold). Evidence of control failures was obtained for bifenthrin, permethrin, diflubenzuron, teflubenzuron, triflumuron and B. thuringiensis. Weather conditions favour resistance to some insecticides, and spatial dependence was observed only for bifenthrin and permethrin. Insecticide resistance in field populations of the tomato pinworm prevails for the insecticides nowadays most frequently used against them – the chitin synthesis inhibitors (diflubenzuron, triflumuron and teflubenzuron). Local selection favoured by weather conditions and dispersal seem important for pyrethroid resistance evolution among Brazilian populations of T. absoluta and should be considered in designing pest management programmes

    Selectivity of eight insecticides to predators of citrus caterpillars

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    O objetivo deste trabalho foi avaliar a seletividade dos inseticidas abamectina, acefato, carbaril, deltametrina, fenitrotiom, fenpropatrina, paratiom metílico e triclorfom aos predadores Brachygastra lecheguana (Latreille), Protonectarina sylveirae (Saussure) e Protopolybia exigua (Saussure) (Hymenoptera: Vespidae) em concentrações que corresponderam a 50% e 100% da dose recomendada para o controle de lagartas em citros. Os inseticidas estudados não foram seletivos em favor do predador P. sylveirae. Fenitrotiom, fenpropatrina, paratiom metílico e triclorfom não foram seletivos em favor dos predadores B. lecheguana e P. exigua. Abamectina, acefato e carbaril foram medianamente seletivos em favor de P. exigua, o mesmo foi verificado com abamectina e carbaril em favor de B. lecheguana. Acefato foi seletivo em favor de B. lecheguana e deltametrina em favor de P. exigua. As altas mortalidades causadas por deltametrina a P. sylveirae, triclorfom a B. lecheguana e acefato a P. exigua decresceram quando aplicados em subdose. B. lecheguana foi o predador mais tolerante à dose de acefato, seguido por P. exigua e P. sylveirae. O predador P. exigua foi mais tolerante à dose de deltametrina que B. lecheguana e P. sylveirae. As três espécies de predadores foram altamente suscetíveis às doses e subdoses de fenitrotiom, fenpropatrina e paratiom metílico, e à dose de triclorfom.The selectivity of abamectin, acephate, carbaryl, deltamethrin, fenitrothion, fenpropathrin, methyl parathion and trichlorfon to the predators Brachygastra lecheguana (Latreille), Protonectarina sylveirae (Saussure) and Protopolybia exigua (Saussure) (Hymenoptera: Vespidae) was evaluated using insecticide concentrations corresponding to 50% and 100% of the current recommended rate for citrus caterpillars. The insecticides studied were not selective in favor of the predator P. sylveirae. Fenitrothion, fenpropathrin, methyl parathion and trichlorfon were not selective in favor of the predator B. lecheguana and P. exigua. Abamectin, acephate and carbaryl showed median selectivity in favor of P. exigua, and the same was observed with abamectin and carbaryl in favor of B. lecheguana. Acephate was selective in favor of B. lecheguana and deltamethrin in favor of P. exigua. The high mortalities caused by deltamethrin in P. sylveirae, trichlorfon in B. lecheguana and acephate in P. exigua decreased when the lower concentration was used. B. lecheguana was the most tolerant predator to the higher acephate concentration, followed by P. exigua and P. sylveirae. P. exigua was more tolerant to the higher deltamethrin concentration than B. lecheguana and P. sylveirae. The three predator species were highly susceptible to both concentrations of fenitrothion, fenpropathrin and methyl parathion, and the higher concentration of trichlorfon

    Caracterização físico-química da polpa e da casca da pitomba brasileira (Talisia esculenta (A. St.-Hill.) Radlk)

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    This study aimed to evaluate the physico-chemical composition and bioactive compounds of pulp and the peel of the pitomba arising from the state of Sergipe/Brazil. The income, the physico-chemical characterization, mineral content, vitamin C and carotenoids of pulp and pitomba peel were determined. The peel presented high income (44,60% of the fruit). A significant amount of vitamin C (20,68 ± 2,93 mg/100g of fresh sample) and carotenoids (43,56 ± 2,04 μg/mL of the extract) were observed in the pulp, while the peel had a high mineral content, mainly potassium (223,00 ± 2,00 mg/100g), calcium (78,90 ± 0,40 mg/100g) and magnesium (47,50 ± 0,90 mg/100g). The constituents’ knowledge of the peel and pulp of the pitomba in natura adds value to the fruit, since it allows a better use of it, considering that the peel is discarded and only its pulp is consumed.Este estudio tuvo como objetivo evaluar la composición fisicoquímica y los compuestos bioactivos de la pulpa y corteza de pitomba del estado de Sergipe / Brasil. Se determinó el rendimiento, la caracterización fisicoquímica, el contenido mineral, la vitamina C y los carotenoides de la pulpa y corteza de pitomba. La cáscara presentó un rendimiento del 44,60% de la fruta. Se observó una cantidad significativa de vitamina C (20,68 ± 2,93 mg / 100 g de muestra fresca) y carotenoides (43,56 ± 2,04 μg / ml del extracto) en la pulpa, mientras que la cáscara presentó un alto contenido de minerales, principalmente potasio (223.00 ± 2.00 mg / 100g), calcio (78.90 ± 0.40 mg / 100g) y magnesio (47.50 ± 0.90 mg / 100g). El conocimiento de los componentes de la cáscara y la pulpa de pitomba in natura contribuye a agregar valor a la fruta, ya que busca fomentar su mejor utilización, teniendo en cuenta que normalmente se descarta la cáscara, siendo solo la pulpa destinada al consumo humano.Este estudo teve como objetivo avaliar a composição físico-química e os compostos bioativos da polpa e da casca da pitomba provenientes do estado de Sergipe / Brasil. Foram determinados o rendimento, a caracterização físico-química, o conteúdo mineral, vitamina C e os carotenóides da polpa e da casca da pitomba. A casca apresentou um rendimento de 44,60% da fruta. Observou-se uma quantidade significativa de vitamina C (20,68 ± 2,93 mg / 100g de amostra fresca) e carotenóides (43,56 ± 2,04 μg / mL do extrato) na polpa, enquanto a casca apresentou elevado conteúdo de minerais, principalmente de potássio (223,00 ± 2,00 mg / 100g), cálcio (78,90 ± 0,40 mg / 100g) e magnésio (47,50 ± 0,90 mg / 100g). O conhecimento dos constituintes da casca e da polpa da pitomba in natura contribui para agregação de valor ao fruto, uma vez que busca incentivar o seu melhor aproveitamento, considerando que normalmente a casca é descartada, sendo apenas a polpa destinada ao consume humano

    Recent Changes in Hydroclimatic Patterns over Medium Niger River Basins at the Origin of the 2020 Flood in Niamey (Niger)

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    Niamey, the capital of Niger, is particularly prone to floods, since it is on the banks of the Niger River, which in its middle basin has two flood peaks: one in summer (the red flood) and one in winter (the black flood). In 2020, the Niger River in Niamey reached its all-time highest levels following an abundant rainy season. On the other hand, the floods in Niamey have been particularly frequent in the last decade, a symptom of a change in hydroclimatic behaviour already observed since the end of the great droughts of the 1970s and 1980s and which is identified with the name of Sahelian Paradox. This study, starting from the analysis of the 2020 flood and from the update of the rating curve of the Niamey hydrometric station, analyses the rainfall–runoff relationship on the Sahelian basins of the Medium Niger River Basin (MNRB) that are at the origin of the local flood. The comparative analysis of runoffs, annual maximum flows (AMAX) and runoff coefficients with various rainfall indices calculated on gridded datasets allowed to hydroclimatically characterise the last decade as a different period from the wet one before the drought, the dry one and the postdrought one. Compared to the last one, the current period is characterised by a sustained increase in hydrological indicators (AMAX +27%) consistent with the increase in both the accumulation of precipitation (+11%) and the number (+51%) and magnitude (+54%) of extreme events in the MNRB. Furthermore, a greater concentration of rainfall and extremes (+78%) in August contributes to reinforcing the red flood’s positive anomalies (+2.23 st.dev in 2020). The study indicates that under these conditions the frequency of extreme hydrological events in Niamey will tend to increase further also because of the concurrence of drivers such as river-bed silting and levee effects. Consequently, the study concludes with the need for a comprehensive flood-risk assessment on the Niamey city that considers both recent hydroclimatic trends and urbanisation dynamics in flood zones hence defining the most appropriate risk-reduction strategies

    Cohabitation inquiline-host in termite nests: does it involve distinct mechanisms?

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    Nests of the termite Constrictotermes sp. can be cohabited by obligatory inquilines Inquilinitermes sp. Recent studies have shown that inquilines establish themselves in mature nests, possibly during the nidification transition phase of the colony (e.g., from the epigeal to the arboreal habit). It is believed that cohabitation is maintained through spatial segregation of the cohabitants since the inquilines aggregate in the central nest region. Here, we described the cohabitation between Inquilinitermes microceus (Silvestri) and a Constrictotermes species in Sergipe, Northeast Brazil. We compared the cohabitation observed in distinct regions considering hypotheses related to the entry and maintenance of the inquiline in the nests. All Constrictotermes sp. nests found in this region are epigeal, unlike already reported in other studies. Approximately 45% of the nests analyzed were associated with I. microcerus, and cohabitation seemed to be dependent on nest size. The entrance of the inquiline was not related to changes in the nidification habit from soil to trees, as suggested in other studies. In addition, inquilines were not associated with and segregated into the dark walls in the central part of the nest. The cohabitation observed here could involve mechanisms which are distinct from the mechanisms reported in other regions

    Cuidados paliativos e qualidade de vida de pacientes com doenças crônicas: uma revisão integrativa

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    Objetivo: Abordar as evidências científicas sobre as estratégias paliativas utilizadas para melhorar a qualidade de vida em pacientes com doenças crônicas ameaçadoras de vida. Metodologia: Revisão integrativa da literatura baseada no seguinte questionamento: Considerando os pacientes com doenças crônicas, quais as estratégias paliativistas e seus contributos na qualidade de vida? O levantamento bibliográfico foi realizado nas bases LILACS e MEDLINE, sendo selecionados artigos dos últimos cinco anos, em português, inglês e espanhol. Resultados: Os seis artigos analisados desvelaram o seguinte eixo temático: Estratégias paliativistas utilizadas para aumentar a qualidade de vida em pacientes com doenças crônicas nas redes de atenção à saúde. Considerações Finais: Este estudo evidenciou estratégias de cuidados paliativos importantes para a qualidade de vida de doentes crônicos, não existindo uma lista ou padrão para essas estratégias, as quais devem ser discutidas e inovadas dentro da equipe de saúde, além de precisarem ser mais estudadas

    Toxicity of the essential oil of basil cultivars and hybrids and its repellent effect on stored grain pests

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    Essential oils have emerged as an alternative to synthetic insecticides in the control of stored grain pests. The toxicity and repellency of the essential oils of four basil cultivars and three basil hybrids and the monoterpenes linalool, citral, and (E)-methyl cinnamate were evaluated in the stored grain pests Callosobruchus maculatus and Sitophillus zeamais. The essential oils of the cultivar Genovese and the hybrid 'Genovese' x 'Maria Bonita' were more toxic to C. maculatus. Conversely, the essential oils of the cultivar Sweet Dani and the hybrid 'Cinnamom' x 'Maria Bonita' were more toxic to S. zeamais. Among the monoterpenes, (E)-methyl cinnamate was the most toxic to both pests, taking 0.14 and 0.34 µL.mL-1 to kill 50% of the C. maculatus and S. zeamais populations, respectively. All essential oils from cultivars, hybrids, and monoterpenes were repellent to S. zeamais, except for (E)-methyl cinnamate. For C. maculatus, this effect was lower, being citral the most repellent compound. Results demonstrate the insecticidal potential of the essential oil of O. basilicum and its monoterpenes in the control of stored grain pests
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